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WISBECH CANAL ENVIRONMENTAL INVESTIGATION DESKTOP STUDY SUMMARY APRIL 2010 This report is a summary of the desk-top study that was carried out in relation to the environmental investigation of Wisbech Canal. A desk top summary is research of map, documents and previous reports relating to a site. This report outlines the site history, previous monitoring and site investigation, contamination and the scope of the investigation. This report is a non-technical summary to provide an introduction into the research behind the environmental investigation. 1 Wisbech Canal Study Summary CHAPTER 1. SITE HISTORY The site which will be investigated is the former Wisbech canal. The canal was 5.25 miles long and extended from The River Nene at Wisbech to Outwell where it joined Well Creek and connected with the River Ouse at Salter's Load Sluice. Because of the low level of the Fens, the canal was built on embankments for some of its length. The canal did not have its own water supply, but was refilled with water at each high tide. Figure 1 shows a diagram of the canal and its bridges and locks. River Nene Wisbech Flood lock Royal Standard PH New Common Bridge Blacksmiths Arms PH Elm Bridge - Prince of Wales PH Collets Bridge (Emneth Bridge) Boyces Bridge Outwell Basin Bridge Inn PH Scotts Bridge Outwell Outwell Sluice Flood Lock Well Creek Figure 1: Diagram of the Wisbech Canal 2 Figure 2: Outwell - Canal, Sluice, Well Creek and tramway in 1800s (Source William Smith) The canal was authorised by an Act of Parliament in 1794 and opened in 1797. A tram line opened to Outwell on 20th August 1883. For a time the tramway helped the canal. The line followed the canal to Outwell Basin, where the first stopping point was. The canal widened at the basin so that barges could turn and moor. The canal carried coal for onward transport to the Fens on barges. The canal and tram also carried fruit back from the Fens. The trams competed with the canal and traffic on the canal stopped in 1922. The canal was abandoned in 1926. A letter on Marshland Rural District Council files dated 4 January 1961 provides reasons why the council wished to fill in the canal. The Clerk of the Council states that since the canal was abandoned it became unused by traffic, derelict and a nuisance.’ The letter goes on to state that in 1944 the Wisbech Canal Corporation were granted powers to pipe and fill in a portion of the canal from the River Nene to New Common Bridge and a large section of this work has been carried out.’ Marshland Rural District Council reached agreement that the land from New Common Bridge to Outwell Sluice should be bought for filling with refuse. 3 Norfolk County Council granted planning permission on 10 th April 1961 for controlled tipping of refuse into the Wisbech Canal ‘In the interests of visual and social amenities of the locality.’ Conditions were placed on planning permission including requirements to tip in layers; cover waste; control fires and vermin; tip from one side at a time; not to raise the surface above adjoining land and avoid pollution of watercourses. A copy of the planning permission (M1661, 1961) and conditions is shown to the left. Figure 3: Planning Permission The landfill area is approximately four and a half miles long. Discussions with people who live locally suggest that the northernmost sections of the canal were filled with generally inert material such as soil. It is thought that domestic waste tipping may have been restricted to the sections of the canal to the south of Elm. Wisbech and Fenland Museum report that the tipping was complete and the Wisbech Canal was finally blocked in the 1970's allowing parts of the A1101, Churchill Road into Wisbech to be built on the route of the canal. 4 A review of the old maps dated 1872 to 1999 was carried out as part of this research. These maps show previous land use and changes over time. Information on residential or commercial land use, natural water features and the many man-made water features can be seen on maps. Figure 4: 1800 OS Map of Outwell Sluice Remains of the old sluice are still visible at Outwell as this picture shows. A map extract is above showing the canal and tramway at Outwell in the 1800s. Figure 5: Photo of remains of Outwell Sluice 5 CHAPTER 2. MONITORING AND SITE INVESTIGATION Cambridge County Council and Norfolk County Council (NCC) took responsibility for the closed landfill as the Cambridgeshire and Norfolk border runs along the centre of the site. Norfolk County Council manages the land on behalf of both County Councils. As the waste can create ground gas such as methane and carbon dioxide (CO 2), NCC carries out monthly gas monitoring from 69 monitoring wells. The land falls in both West Norfolk and Fenland administrative areas. Monthly gas monitoring by NCC to the south of the A47 has shown carbon dioxide in several monitoring wells within the waste. Recently methane has been detected in two locations. Norfolk County Council reports that the old canal immediately north of the A47, Wisbech bypass, was believed to be filled with soil and rubble. Figure 6: photo of gas monitoring well In 1991 some holes were dug approximately three metres deep in this area. These showed soils, rubble and some timber. Gas wells were installed in the holes and the gas in the wells was measured four separate times. Monitoring was stopped when no methane was detected and only slightly elevated levels of carbon dioxide. Where new buildings are proposed within 250m of the infilled canal both West Norfolk and Fenland Councils planning permission asks for a gas risk assessment. The presence of some gas has been reported and gas protection has been included in new buildings. However, the source of the gas has not been proved. NCC have researched some areas of the infilled canal where it is proposed to sell the land to local residents. In these areas the land is used as amenity land, residential gardens or vegetable patches. Copies of the research were supplied to potential buyers. 6 Hand dug samples As part of this investigation, soil samples were taken from four locations and submitted for laboratory analysis on 14th January 2010. This part of the investigation aimed to show what contaminants might be present in soil near the surface. Samples were collected at 0.2m and 0.5m below ground level. Where waste was present at the surface a sample was collected of the waste material. Figure 7: Ph oto of disturbed waste Table 1: Hand dug samples soil descriptions Location Depth below ground and description HA1 Elm open 0.0-0.2m Brown clayey topsoil space 0.2-0.5m Light brown soil with some brick, stone and ash fragments HA2 0.0-0.2m Brown sandy clay with brick and flint fragments and Embankment some black plastic sacks south of Collets 0.2-0.5m Becoming more sandy, orange brown with brick and Bridge numerous flint fragments HA3 East of Land recently disturbed for underground service excavation Outwell Basin 0.0m Waste on surface, fabric, clothing, shoes, bottles, plastic, detergent bottles, organic material and vegetation 0.2m Brown soil some glass and organic material 0.2-0.5m Buff sandy fill, some stones, obstruction at base HA4 Adjacent to 0.0-0.2m Very stony brown soil gas well 68 and 0.2-0.5m Very stony brown soil with flints former sluice Laboratory analysis suggested there were contaminants in the waste such as lead, oil or ash higher than would be expected in local soils. 7 CHAPTER 3. CONTAMINANTS, PATHWAYS AND RECEPTORS The purpose of site inspection is to find if humans or other subjects such as buildings, crops or water could be harmed by contamination. Subjects that could be harmed are called ‘receptors’. ‘Pathways’ is the word used to describe how contamination could travel to the receptor. Examples of pathways are people touching soil or movement of gas from the soil into a house. To decide if there may be a risk to human health or other receptors it is necessary to find out: 1. What contaminants may be present; 2. Who or what (receptors) are present on the site or close by (humans, water, property); 3. What pathway the contaminant could travel along to reach the receptors Contaminants Information from the library and local archives, reports like the Department of the Environment Industry Profiles and research documents published by the Environment Agency were used to find out what contaminants might be found in the waste material and surrounding soil. A site walkover survey was carried out to look for evidence of the canal and fill materials. Table 2 indicates some of the contaminants that research showed could be found in waste materials. As the waste rots it can produce methane gas or carbon dioxide gas. Table 2: Sources of Contaminants Source Contaminants Landfilled Oil/fuel hydrocarbons, Polyaromatic hydrocarbons, wastes Chlorinated hydrocarbons, PCBs, Metals, Sulphate, Asbestos, Carbon Dioxide gas, Methane gas, Dioxins and Furans The line of the canal could be seen clearly from the site walkover. Some areas of uneven ground indicate where the waste material has settled or where different soils were used to cap the waste. Uneven ground can also be a sign that some organic waste has rotted away underground. 8 Pathways Local geology was studied to see if contaminants from the waste could travel in water or vapours from the landfill towards nearby receptors.